SpriteForge

Spec sheet

Purpose

SpriteForge is a browser-based editor for rigged 2D sprite animation.Read 9 Oct 2026 · github.com

Intended users

The project is aimed at small teams, game-jam projects, tool hackers, and people seeking a lightweight 2D rigging workflow.Read 9 Oct 2026 · github.com

Integrations

The specification says exported Spine JSON can be used with runtimes including Phaser, PixiJS, Unity, Godot, and custom runtimes.Read 9 Oct 2026 · github.com

License

The repository lists an MIT license.Read 9 Oct 2026 · github.com

Animation features

The editor includes a timeline with keyframes, easing, curve previews, undo and redo, and two-bone inverse kinematics.Read 9 Oct 2026 · github.com

Browser support

The specification lists desktop support for the latest two versions of Chrome, Firefox, Safari, and Edge, and says mobile/touch editing is unsupported.Read 9 Oct 2026 · github.com

Development status

The repository describes SpriteForge as an early open-source release and says several advanced animation features are still in progress.Read 8 Oct 2026 · github.com

Export formats

Exports include Spine 4.x-style JSON, atlas and PNG files, a standalone runtime.html player, and MP4 previews.Read 9 Oct 2026 · github.com

Exports

SpriteForge exports Spine-style JSON, atlas, and PNG bundles, plus MP4 previews using H.264 via ffmpeg.wasm.Read 8 Oct 2026 · github.com

Feature status

The project describes itself as an early open-source release, and says some advanced animation features remain in progress.Read 9 Oct 2026 · github.com

How it works

Users import images, create a bone rig, keyframe animation, and export a Spine-compatible JSON, atlas, and PNG bundle.Read 9 Oct 2026 · github.com

Image and mesh features

It supports PNG/JPG insertion, TexturePacker-style sprite sheet import, mesh attachments with GPU skinning, and automatic weight recomputation.Read 8 Oct 2026 · github.com

Image import

SpriteForge supports PNG and JPG images and TexturePacker-style sprite sheet import.Read 9 Oct 2026 · github.com

Import compatibility

Spine bundle import is partial and may omit constraints, non-default skins, FFD, events, draw order, and linked meshes, with warnings.Read 9 Oct 2026 · github.com

Import limits

Spine 4.x bundle import is partial and omits constraints, non-default skins, FFD, events, draw order, and linked meshes, with warnings.Read 8 Oct 2026 · github.com

Local operation

The editor runs in the browser, with no account, server, or upload pipeline; project data and images stay on the user's machine.Read 9 Oct 2026 · github.com

Local use

The project says it runs in a browser tab without an account, server, or upload pipeline, keeping projects and images on the user's machine.Read 8 Oct 2026 · github.com

MP4 limitation

MP4 export uses ffmpeg.wasm, whose large bundle can make the first export slow; GIF export is not supported.Read 9 Oct 2026 · github.com

Notable missing features

Brush-based weight painting, full mesh edge split/merge tools, full FFD workflow, and multi-bone and path inverse kinematics are listed as incomplete.Read 8 Oct 2026 · github.com

Privacy and telemetry

The repository describes its privacy model as local-first, with no telemetry or uploads.Read 8 Oct 2026 · github.com

Project files

Editable projects use the .sfproj format, which stores project data and embedded image data.Read 8 Oct 2026 · github.com

Project storage

Editable projects use the .sfproj format and autosave in browser localStorage.Read 9 Oct 2026 · github.com

Rigging and animation

Users can import images, build a parent-child bone hierarchy, pose characters, and animate them on a timeline.Read 8 Oct 2026 · github.com

Runtime integration

Exported bundles are intended for compatible Spine-style runtimes and can also be previewed in the included standalone runtime.html player.Read 8 Oct 2026 · github.com

Timeline features

The timeline supports keyframes, copy and paste, duplication, easing presets, curve display, and undo and redo.Read 8 Oct 2026 · github.com

Where Specifiction places it

• 2D Character Animation Software#39 of 487.1
• 2D Game Animation Software#23 of 257.0